[PATCH AUTOSEL 6.14 519/642] net: ethtool: prevent flow steering to RSS contexts which don't exist

Sasha Levin
2025-05-05T22:35:34Z

From: Jakub Kicinski <kuba@kernel.org>

[ Upstream commit de7f7582dff292832fbdeaeff34e6b2ee6f9f95f ]

Since commit 42dc431f5d0e ("ethtool: rss: prevent rss ctx deletion
when in use") we prevent removal of RSS contexts pointed to by
existing flow rules. Core should also prevent creation of rules
which point to RSS context which don't exist in the first place.

Reviewed-by: Joe Damato <jdamato@fastly.com>
Link: https://patch.msgid.link/20250206235334.1425329-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ethtool/ioctl.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 1c3ba2247776b..0d3a70a18884f 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -993,10 +993,14 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
return rc;

/* Nonzero ring with RSS only makes sense if NIC adds them together */
- if (cmd == ETHTOOL_SRXCLSRLINS && info.fs.flow_type & FLOW_RSS &&
- !ops->cap_rss_rxnfc_adds &&
- ethtool_get_flow_spec_ring(info.fs.ring_cookie))
- return -EINVAL;
+ if (cmd == ETHTOOL_SRXCLSRLINS && info.fs.flow_type & FLOW_RSS) {
+ if (!ops->cap_rss_rxnfc_adds &&
+ ethtool_get_flow_spec_ring(info.fs.ring_cookie))
+ return -EINVAL;
+
+ if (!xa_load(&dev->ethtool->rss_ctx, info.rss_context))
+ return -EINVAL;
+ }

if (cmd == ETHTOOL_SRXFH && ops->get_rxfh) {
struct ethtool_rxfh_param rxfh = {};
--
2.39.5